The present disclosure relates to a semiconductor device, and particularly to a semiconductor device including a trench capacitor, an access transistor, and an embedded strap providing a conductive path between an electrode of the trench capacitor and a source region of the access transistor, and methods of manufacturing the same.
Trench capacitors are employed for various applications including stand-alone dynamic random access memory (DRAM) devices, embedded DRAM devices, and decoupling capacitors. Some applications of the trench capacitors require a low resistance electrically conductive path to an electrode of a trench capacitor. For example, high performance embedded eDRAM devices require a conductive path between an inner electrode of a trench capacitor and a source region of an access transistor.
A silicide strap formed between an inner electrode of a trench capacitor and a source region of an access transistor can have yield problems due to the proximity of a trench top oxide (TTO), which can cause formation of divots at an interface between the inner electrode of the trench capacitor and the source region. The divots can be filled by a non-conductive foreign material, or may remain unfilled after formation of a silicide buried strap. In such cases, the electrical connection between the inner electrode of the trench capacitor and the source region can be a source of a yield problem or a reliability problem. Thus, a more robust and manufacturable structure for an electrically conductive path between an inner electrode of a trench capacitor and a source region of an access transistor is desired.